The present invention relates to a device that includes a hydraulic motor which is operable to drive an output shaft and a brake assembly which is engageable to hold the output shaft against rotation when the motor is in an inactive condition.
A known hydraulic device having a motor which drives an output shaft and a brake assembly which holds the output shaft against rotation when the motor is in an inactive condition is described in U.S. Pat. No. 3,960,470, issued June 1, 1976 and entitled "Hydraulic Motor Brake". This known hydraulic device includes a motor of the gerotor gear type. During operation of the motor, a rotor orbits and rotates relative to a stator. A portion of a wobble or drive shaft is connected with the rotor for orbital and rotational movement with the rotor. An outer end portion of the drive shaft is telescopically received in a hollow inner end portion of an output shaft. During operation of the motor, the drive shaft rotates the output shaft.
The hydraulic device of the aforementioned U.S. Pat. No. 3,960,470 includes a brake assembly which is connected to a portion of the drive or wobble shaft and is disposed on a side of the motor opposite from the output shaft. The brake assembly includes movable disks which rotate and orbit with the drive shaft during operation of the hydraulic motor and stationary disks which are interleaved with the movable disks. When the motor is in an inactive condition, the movable and stationary brake disks are pressed together to hold the drive shaft and, therefore, the output shaft against rotation. When the motor is to be operated, the brake assembly is released to enable the drive shaft to rotate and orbit.